By Michael Hightower
Distinguished Member of the Technical Staff, Sandia National Laboratories for Cornerstone
Water is an essential natural resource that impacts all aspects of life: Clean and abundant supplies of water are vital for supporting the production of food, public health, industrial and energy development, and a healthy environment. Water is an integral part of energy extraction, production, and generation. It is used directly in hydro-electric power generation and is used extensively for thermoelectric power plant cooling and emissions control. Water is also used for energy resource extraction such as gas shale fracking and development, biofuels production, coal and uranium mining and processing, as well as for oil and natural gas refining and energy resource transportation.
Historically, energy infrastructures around the world were commonly developed within a context of unconstrained water resource availability. Increasingly, however, unsustainable uses of water resources, population dynamics and migration patterns, and climate change impacts on precipitation and the environment are all altering the baseline supplies of water across the globe. These factors are affecting new energy generation needs, the timing and spatial patterns of energy demand, and the risk factors for energy security, reliability, and price stability.
Therefore, as nations try to balance the demands and availability of water resources to support growing agricultural, human health, energy, industrial, and ecological demands in the coming decades, it is clear that the water footprint, even more so than the carbon footprint, could become the critical factor in defining a secure, resilient, and sustainable energy future for countries around the world.
A Collision Course between Water Supplies and Energy Development
The growing concerns about the conflicts between water resource availability and the ability to support sustainable energy growth were first highlighted in a U.S. Department of Energy Report to Congress prepared in 2007 by Sandia and Los Alamos National Laboratories in cooperation with the National Energy Technology Laboratory and the Electric Power Research Institute (EPRI).1 That report noted a number of trends in water resource availability and growing water demands that could significantly challenge energy growth, reliability, and sustainability.
Since then, concerns over growing water constraints and their impact on future energy development have been recognized by energy, water, and financial and economic development leaders worldwide. The trends observed include the stress in water resource availability in many regions of the globe and how that is being exacerbated by climate change, the growing water needs to support industrial growth and public health that will increase competition for water resources, and the growing trend in implementing higher water-intensive energy technologies. These three trends suggest a collision course between sustainable water resources management and sustainable economic growth, public health, and secure energy supplies in the coming decades. The following sections highlight both the growing water and energy interdependency concerns and the research, development, and technology innovations needed to reduce energy water needs and drive toward a more sustainable water and energy future.
Emerging Energy and Water Issues and Challenges
One of the major challenges facing new energy production and generation globally is the current high level of water stress relative to water supply availability around the world (see Figure 1). The projected growth in global energy development and the estimated increase in water consumption will occur in regions where freshwater availability is already under high stress due to a combination of demands from major water-using sectors and unsustainable surface water and ground-water withdrawal practices.
Figure 1. Current water-stressed regions of the world.
Source: World Resources Institute Aqueduct Water Risk Atlas
Unfortunately, precipitation reduction in many of the mid-latitude regions is expected to reduce fresh surface water supplies by 20–40% by mid-century due to changing climate patterns, suggesting even greater water supply stress in many regions in the near future.
A second concern is the growing water demand of new energy technologies. A recent study by the International Energy Agency, presented in their 2012 World Energy Outlook, projects world energy demand will grow by as much as 30% by 2035, but that water consumption for energy generation and production will increase by 85%.2 This suggests that much of the new energy generation will require greater water use and water-consumptive energy technologies. Table 1 compares the water consumption of some traditional and emerging energy generation and production technologies for electric power, transportation fuels, and natural gas.3
As can be seen, many of the new energy approaches being suggested to reduce greenhouse gas emissions, such as carbon capture, nuclear energy, concentrating solar-thermal, and biofuels, are all two to four times more water intensive than the traditional energy approaches they are replacing. Some approaches—including irrigated biofuels, which consumes 2000 times more water than traditional oil-based fuel production—are even more water intensive. Some renewable technologies, such as wind and solar photovoltaics, as well as new thermoelectric cooling technologies like dry cooling, require very little water. However, these approaches currently all have reliability and year-round availability concerns for many regional applications. This illustrates that major energy policies need to consider system-level natural resource impacts in order to better support sustainable water, energy, and natural resource conservation efforts in the future.
A third concern is the growing water demand by other major water use sectors to support population and economic growth, and the need for additional domestic water supplies to support improved public health and sanitation, especially in developing regions such as Asia, South America, and Africa. In these areas, projected water demand growth is 10–20% for the agricultural sector and 30–40% for the domestic water supply sector by 2035. Table 2 provides an overview of the relative water use by sectors for developed and developing regions of the world.4,5
As highlighted in Table 2 and noted in a report by the World Economic Forum in 2009, developing countries could need to increase water allocated for energy development by a factor of three to four to approach the current levels of energy infrastructure in developed countries.6 This is expected to put the energy sector into increased competition with other sectors for already-limited water supplies in many countries. This was also highlighted by the World Energy Council in their 2010 Water and Energy report, which identifies several regions of the globe where water supply availability is currently insufficient to meet proposed energy development.7 The competition for water resources to meet the growing water demands in several sectors could pose a serious challenge to many countries, especially many developing countries, to create sustainable energy and water development strategies over the next several decades.
Table 2. Global water use by sector
Examples of Water Impacts on Energy Generation
In Sandia’s original efforts to support the U.S. Department of Energy’s report to Congress on energy and water interdependencies, we highlighted many cases across the U.S. from 2004 through 2007 where power plants or biofuel refineries had been denied permits because of the lack of water availability in the region. Since that time, we have seen instances of droughts in Texas and the Southwest, the Southeast, and the Northeast U.S. that have caused a large number of coal and nuclear power plants to reduce or stop operations because of low water flows or high water temperatures in the receiving waters that reduced cooling capacity. Since 2005, France has been forced to curtail electric power production of their nuclear and hydropower plants by as much as 20% in three different years, due to low water flows and high water temperatures during heat waves. In India, in February 2013, a thermal power plant with an installed capacity of 1130 MW shut down due to a severe water shortage in the Marathwada region. Many power plants in South Africa have already converted to dry cooling to address the reductions in water supplies over the past few decades. Recurring and prolonged droughts are threatening hydropower capacity in many countries, such as Sri Lanka, China, and Brazil. These stresses will mount as some emerging economies double their energy demands in the next 40 years.
Driving Toward a Sustainable Energy and Water Future
To help develop a dialogue on how to address these growing concerns, many agencies have studied ways to reduce these emerging energy and water impacts. For example, Sandia conducted a series of national workshops in the U.S. to identify research areas and innovative approaches to reduce freshwater use by the energy sector and improve water availability.3 Since then, many other groups in the U.S.—including the National Science Foundation, the General Accountability Office, the National Research Council, the Electric Power Research Institute, the Department of Energy, and non-profits like the Johnson Foundation—have identified innovative approaches to help address identified issues and concerns. Internationally, organizations such as the United Nations, the World Bank, the World Council on Sustainable Development, and the Canada Institute have undertaken efforts to help develop and implement innovative low-water-use technologies or approaches in energy development. Not surprisingly, most ideas fall into one of the four major categories outlined below.
Reduce freshwater consumption for electric power and transportation fuels. Many approaches exist that could help reduce freshwater consumption for electric power generation. However, technologies like dry and hybrid cooling and low-water-use renewable energy technologies have cost or intermittency issues that must be improved. Since virtually all new alternative transportation fuels will increase water consumption, major scale-up of these fuels must include approaches that use less water for growing, mining, processing, or refining.
Develop materials and water treatment technologies that more easily enable use of nontraditional water resources. With freshwater supplies becoming more limited, wastewater reuse and nontraditional water use, including seawater, brackish groundwater, and produced water, will be needed. New water treatment technologies that can meet emerging water quality requirements at much lower energy input will be important. These improvements could reduce energy use for water treatment and pumping, while accelerating the use of nontraditional water resources in the energy sector, such as for cooling or hydraulic fracking.
Improve water assessment and energy and water systems analysis and decision tools. Compounding the uncertainty of available water supplies is a lack of data on water consumption. Improved water use and consumption data collection and better water monitoring are needed. Improved decision support tools and system analysis approaches are also needed to help communities and regions better understand and collaborate to sustainably develop solutions that minimize freshwater demand and consumption. Another need is the development of regional climate change models that can better predict regional- or watershed-level impacts of climate variability on items such as precipitation and evapo-transpiration. These capabilities will help support a better understanding of water resource availability and support improved water management.
Improve opportunities to integrate energy and water infrastructure planning. Currently, water and energy infrastructures are often managed independently. There are potential economies of scale by integrating or colocating energy and water infrastructure and conducting integrated planning. Waste heat from power plants or refineries and wastewater from water treatment plants could be better utilized to reduce usage of both energy and freshwater resources.
In the private sector, companies and associations have already started to leverage their talent and resources to address these issues. For example, EPRI and their power utility affiliates have initiated studies of new low-water-use cooling approaches and have helped develop a $16M large-scale testing facility at a power plant in the southeastern U.S. to test innovative, low-water-use cooling technologies. The data collected is being shared with European power companies. Coal producers are exploring alternative sources of water, such as desalination, and using mine water to reduce freshwater use. In the oil and gas area, companies in both Canada and the U.S. have started implementing approaches to use brackish water and reuse water in oil sands and hydraulic fracturing to minimize both the use of freshwater and wastewater disposal. These efforts have increased fuel production while significantly reducing freshwater use. These examples highlight the broad focus needed to develop a more balanced use of natural and financial resources by looking at additional environmental metrics, such as the water footprint, to help drive and develop a sustainable energy future.
The content included in Cornerstone is based on the opinion of the authors, and does not necessarily reflect the views of the World Coal Association or its members.
- U.S. Department of Energy. (2007, January). Energy demands on water resources: Report to Congress on the interdependency of energy and water, www.sandia.gov/energy-water/docs/121-RptToCongress-EWwEIAcomments-FINAL.pdf.
- International Energy Agency. (2012, November). World energy outlook 2012.
- Pate, R., Hightower, M., et al. (2007, March). Overview of energy-water interdependencies and the emerging demands on water resources. SAND2007-1349C. Sandia National Laboratories.
- Organization for Economic Cooperation and Development. (2007). Environmental outlook baseline 2007. Paris, France, wmc.landfood.ubc.ca/webapp/VWM/course/global-water-challenges/rainfed-vs-irrigated-agriculture/
- Schreier, H., & Pang, G. (2012). Virtual water and global food security, www.wmc.landfood.ubc.ca/webapp/VWM/
- World Economic Forum (2009). Energy Vision Update 2009: Thirsty energy: Water and energy in the 21st century, www3.weforum.org/docs/WEF_WaterAndEnergy21stCentury_Report.pdf
- World Energy Council. (2010, September). Water for energy, www.worldenergy.org/documents/water_energy_1.pdf
The author can be reached at email@example.com